SIGHTING RIFLES.
On most long,-range rifles, the rear is made with a vernier scale operated by a screw, by which an alteration of one-hundreth of an inch. and even of half that amount, can be made in the elevation, the result being exact, and recorded in figures—the only way in which a correct record of elevations can lie kept. On the Remington rifle the divisions on the vernier are termed degrees and minutes, and on the Sharps decimals of an inch. On the former each minute is 1-92 of an inch, and corresponds upon a 34-inch barrel with 1-18 of an inch, at each too yards. On the Sharps, rifle each sub-division is I-100 of an inch, correspond ing theoretically to I 1-2 11161 to every one hundred yards. As no man can hold or sight a rifle at ',ono yards within ten inches, the elevation on both rifles is practically the same, or about two inches to each too yards for each sub-division on the vernier that is, twenty inches at L000 yards. The sub-divisions upon the wind-gauge of both the Remington and Sharps rifles are about 1-4o of an inch, and are equivalent in practice to two inches at each 100 yards, or 20 inches at i,000 yards, on the 34-inch barrel.
As the errors incident to aiming, at long range will, in most cases, increase the effect of any alteration in the sig,lits, care should be taken to keep well within the elevations which would be mathematically corre'ct. It must also be recollected that the velocity of a bullet decreases with the distance, and as it loses its velocity it becomes more likely to be affected by currents of air. Ccmsequently the effect of any change upon the sights is greater proportionately at long than at short range. The effect of wind, etc., increases in a still greater proportion, that which would require an alteration of 2 points in the elevation at Soo yards, requiring 2 1-2 at 900, and 3 at 1,000. The proportions of the trajectory represented in the above sketch arc exaggerated with respect to the size of the rifle. In estimat ing the carrying power of any bullet, it is customary to give. as the measure of its trajectory, the mid-range height of the bullet above the straight line from the muzzle of the rifle to the point where it strikes the targ,et. The best riflemen pre fer to have the peep-hole of the rear sight of considerable size, as affording more light, and consequently allowing- a better sight to be taken. In the 1\letford rear
sight, discs having different sized apertures may be used: and it has been stated ? by some of the Irish team that they have, in foggy or dark weather, done good shooting- by removing the disc entirely, so as to leave an aperture of nearly a quarter of an inch. Every rifleman should, therefore, have an extra disc, with a large aperture, to use in dusky weather. The vernier sight is usually placed upon the small of the stock. General Dakin and others who shoot on their backs, have it placed upon the heel of the butt. When the latter is th(..‘ case, it makes the dis tance between the two sig,lits nearly a third greater than when placed upon the small of the stock. and consequently a proportionately greater allowance both for elevation and wind will be required.
In order to acquire a correct manner of aiming with the various sights adapted the following, directions given for Winchester repeating and sin.r,de shot rifles should be observed: The rifle should be held with its butt placed firmly against the shoulder, yet not so tightly as to cause any muscular strain or tremor. and its muzzle brought to point in the direction of the target. but somewhat below the bull's-eye; care being- taken to keep the sig,hts perfectly upright. The center of the notch in the rear sight should then be brought into direct alignment with the front sight ; and when correctly held the tip of the front sight should appear about 1-32 of an inch above the bottom of the notch of the rear sight, or so much as may be distinctly seen without blurring-. \Vith a bead or pin-head front sight the whole of the bead should be seen. Keeping the sights in this same relative position, the muzzle of the rifle should be raised until the tip of the front sight reaches the bottom edge of the bull's-eye. but does not quite touch it ; a small space interven ing just perceptible to the eye without straining. With aperture front sights, the aperture in the bead should "ring- the bull's-eye, allowing a thin white ring to show equally around the bull's-eye.